Wood tubing manufacture



' June 11, 1946.

P.- R. GOLDMAN ETAL WOOD TUBING MANUFACTURE Filed May 28, 1943 Patented June 11, 1946 I 2,402,038 WOOD rusmc MANUFACTURE Paul R. Goldman,

Andover, and Rudolph Alt,

Lawrence, Mass, assignors to Plymold Corporation, Massachusetts Lawrence, Mass.,

a corporation of Application May 28, 1943, Serial No. 488,854

4 Claims.

Our present invention concerns the manufacture of wood veneer or plywood tubing of general utility. More particularly it aims to provide a novel method or process, whereby tubing of the described character and of indeterminate length may be rapidly and inexpensively produced endlessly and automatically in the course of a unifled manufacturing operation which is continuous from start to finish of the tubing product. Under the invention such process comprises a series of progressive operational steps each correlated and synchronized with the others and subject to modification as to their number and order according to the particular circumstances and the desired structure for the given tubular product.

In the accompanying drawing illustrating largely diagrammatically and by way of example suitable apparatus for the practice of our improved process,

Figs. 1, la. and 1b, the two latter a continuation of Fig. 1 are a schematic showing in plan of a series of stationsof a typical apparatus for forming the endless tubular product.

As will be evident from the schematic illustration, the tubing process as a whole cgmprises a succession of stages or phases each involving one or more operative steps, all performed along a series of. independently controllable but synchronized and coordinated stations. The mechanical and electrical equipment at the various stations is disposed as an organized assembly of units distributed along a sectionalized or other suitable frame represented in the drawing as including longitudinal members 2 and cross supports 3, the construction desirably being such that units may be added or omitted as particular tubing products and uses may require. In the diagrammed example some sixteen such stations or operational phases are indicated generally by the reference letters A to P, the supporting frame asa whole desirably being of a sectional character. To promote proper relative timing of all movements and phases of the apparatus as a whole the several units or sections are represented as operated from a common drive shaft 4 rotatably supported along the machine frame in suitable bearing brackets 4'.

The base or inner veneer layers which provide a core for the tubing product are developed upon an elongated cylindrical or other former or mandrel 5. This is of a length to extend'at least through the initial spiral wrapping and bonding stations B and C and preferably along one or more succeeding stations, herein through station H. While in some instances a rotary mandrel may be employed, we prefer a stationary-nonrotating mandrel such as here shown at 5. It accordingly may be fixedly supported at its initial or rear end in station A. Forwardly thereof it is freely supported for reception of windings of veneer, as by means of radially yieldable roller th r e in s at or between stations, as at the cross supports 3 and which in eifect afford the mandrel a floating mount.

The tubular product comprising the several superposed and interbonded veneer layers or wraps is caused to progress along the non-rotated mandrel to the forward terminus thereof and thence on throughout the full length of the machine in a continuous length of indeterminate extent. As noted, the one or more inner or core wraps of the veneer preferably are spirally formed. In feeding or advancing them along and past the mandrel, any tractive or progressing action should be so applied as to avoid the tendency of opening or separating the spiral turns. Accordingly our process desirably includes a continuous supporting of the tubing by means adapted to travel with it and to distribute the progressing force along the entire length of the developing spiral tubing, in effect overlapping and bridging across between its multiplicity of spiral turns, This may be accomplished through the medium of a progresser element, feeder or carrier represented as a longitudinally continuous web ,or layer 6 of foldable sheet material.

This carrier is conducted from a suitable supply, along onto and about the mandrel, concentrically between it and the spiral-laid veneer above-mentioned. Selected flexible sheet material of adequate tensile strength may be employed for the purpose, such for example as a fairly heavy waxed paper strip, a light-weight cotton or other fabric web or the like. A supply roll 6a of such material is rotatably mounted at or adjacent station A, as upon a bearing shaft I, in position to be drawn upon. The carrier strip 6 from the supply passes about a guide roll 8 and forwardly through a former 9 shaped and positioned to fold the longitudinal side edges of the advancing carrier strip laterally about the mandrel 5, so as to enclose or partly enclose it. At the start of a manufacturing operation, such feeder or carrier strip 6 has its leading end threaded through the former 9 and forwardly along the mandrel 5 to or beyond the point, herein at station E, where the first veneer spiral wrapping is to be applied, such wrapping then serving to hold the strip in position about the mandrel.

At station B, a first strip 1 of thin wood veneer is spirally applied, with the succeeding veneer turns in closed or substantially closed edgewise abutting relation. Such veneer strip may be of the character as described for'example in the copending Goldman application Ser. No. 462,800, now issued as Patent No. 2,388,479, dated November 6, 1945, extensive lengths of this strip material being prepared and supplied in roll form.

A supply roll H of such veneer strip or tape is rotatably mounted on an arm 12 pivoted as at E3 on a revoluble wrapper head indicated generally at M. The latter is driven by suitable connections i5, desirably of a positive chagacter, from the main drive shaft 5, through an interposed variable speed control device iS, affording independent adjustment and control of the speed of the wrapping operation at this station B. It will be seen that the bodily revolution of the veneer tape supply roll or drum 1 I about the mandrel is effective to wind spirally onto the paper, fabric or like carrier strip 6 on the mandrel a layer of the veneer stripping having a direction of wind, indicated as right hand at station B corresponding to the direction of revolution of the wrapper head, assumed in this instance as clockwise as viewed from the rear end of the machine, at the left in Fig. 1. This initial veneer wrap it as at station B may be of either hand, subsequent wraps preferably being alternately opposite to the one preceding.

From station B the initial veneer layer it] is advanced along the mandrel together with the carrier web 5 whereby undesired separation of the spiral turns is avoided, to station C. There a second layer of veneer stripping 20 is spirally applied. Similar veneer wrapping mechanism is" provided at station C, like parts accordingly being indicated by similar reference numerals as for station B, These include a further veneer supply roll H rotatable on a pivoted arm l2 and bodily revoluble with the wrapper head I4 actuated from the common drive 4 through connections 95 again including a variable speed control it. The gearing is here arranged to afford direction of revolution for the wrapper head opposite that at the preceding station B.

Attendant on the formation of the second spiral veneer wrap 20, the two initial layers l0 and 20 are united throughout their entire lengths by the medium of a plasticizable bonding agent, under the application of heat and pressure. For this purpose we employ a Dlasticizable thermosetting or thermo-plastic bonding agent of the synthetic or other resin type adapted for setting or polymerizing in the presence of pressure and heat. While we prefer for the purpose a phenolic cement, glue or like adhesive and impregnating agent, various materialsare available, including those of the urea type and others as more fully disclosed for example in the prior applications of the applicant Goldman, Serial Nos. 448,819, 467,243 and 473,212, the two latter applications now having become Patents 2,352,533, dated June 27, 1944, and 2,348,291, dated May 9, 1944, respectively,

The selected bonding agent preferably is applied as a step in' the preparation of the veneer strip or tape supply rolls, as'a coating or e, juxtaposed layer which is dried before the strip is wound into the form of a supply roll. But one layer or coat of the bonding agent generally is required between any two succeeding veneer wraps. Hence it may be carried either at the outer face of a first roll supply, such as that for station B, or at the inner face of any following roll supply, such as for station C and others subsequent. Or as to any stations except the first and last. the bonding material may be supplied at both faces of the veneer strip. The process as a whole is facilitated by thus preliminarily applying the bonding agent to the veneer strip of the supply rolls, but in some instances the agent may be applied to or inserted between the succeeding veneer layers in the course of the advance of the tubing product through the machine.

The tubular veneer layers l0 and 20, as well as the others, are caused to advance, progress or travel bodily along the forming mandrel 5 by means to be referred to later in connection with station D and others; in the course of this travel the veneer layers are subjected to heat and pressure so calculated and timed withrespect to the particular bonding agentemployed as to set or polymerize the same at least adequately to afiord the progressing tubular structure a self-sustaining integral character. That is, the veneer layers to be joined such as I0 and 20 of stations B and C receive a heat and pressure treatment such that upon their arrival at a next station the are sufficiently firmly set to receive a further superposed veneer layer without likelihood of being deformed, separated or otherwise disturbed by the latter. This polymerizing, setting and drying of the bonding agent need not be wholly complete or final between successive wrapping stations and generally maybe continued and supplemented in the course of similar treatment of succeeding layers, so that at the delivery station P a completed tubing product is endlessly delivered, subject to such, if any, buffing, coating or other finishing treatment as may be desired in a given case.

While the heating and pressure treatment may be variously accomplished, we have found particularly adapted to the purposes of our process a treatment involving the application of electric energy either of the high-frequency or radiofrequency character or as utilized in electrical resistance heating. Accordingly we have herein diagrammatically indicated in association with station C, and various subsequent stations, means whereby the bonding agent is subjected to heat created by high-frequency or radio-frequency current while simultaneously the layers to be bonded are placed under pressure tending to compact and unify them. Heating of the character referred to, sometimes termed diathermic, may in general be such as described for example in British Patent No. 310,925, U. S. Patents Nos. 1,813,425 and 1,900,573, and others such as 2.087480 and 2,173,622.

Such heating and pressure means as here diagrammatically ShOWn includes one or more rolls 22 mounted for rotatable pressing engagement upon and around the outer surface of the then outer or second veneer wrap 20, in opposition to the mandrel 5 utilized as a former or die. These pressure rolls 22 or their surface portions are of metal. or other conductive material suitably insulated from their supporting means. They are simultaneously utilized as electrodes, being connected in circuit with one side, either positive or negative, of a source of high-frequency or radiofrequency current, as indicated diagrammatically at station 6. The other electrode is presented by the mandrel 5 itself, the latter being insulated from its bearing supports and being connected heat and pressure over a substantial length of the tubing, adequate to accomplish the setting and drying of the bonding agent during the timed progress of the tubing beyond station C. Said elements may comprise a single elongated set or a series of successive sets distributed along the tubing.

It will be evident that the polymerizing time for the particular bonding agent employed is a main factor in determining the rate of advancing travel for the forming tubular structure. Under the process of our present invention, the several operational stations are so arranged and correlated, and the rate of travel of the tubing product is so timed that in the course of progress from one wrapping or layer-applying station or point to the one next'succeeding the bonding agent is at least partially polymerized, to the unifying extent as previously described, adequately to render the product substantially self-supporting with a penetraor form-retaining, as to each succeeding veneer layer and as to the accumulating unified plurality thereof as a whole.

At station D we have represented schematically a progressing or advancing means as particularly appropriate in association with the assumed stationary and non-rotating mandrel 5. It comprises as a main element an endless flexible band or feeder belt 25. One or more full turns of this belt are applied directly around and in gripping engagement with the outer surface of the tubingv ill-20. The belt also passes over one or more carrier pulleys on a revoluble head or plate 26 having a supporting sleeve bearing 21 surrounding and-concentric with the tubing but spaced from it. This head 26 is driven through suitable connections 28 from the main drive shaft 4, again through a variable speed control unit 29.

The feeder belt 25 as stated has one or more full turns, in side-by-side relation, around the tubing, where it accordingly presents a spiral or screw-like gripping formation. Revolution of the belt as a whole, while the belt itself is kept taut between its carrier pulley and engaged tubing, produces a, similar effect upon the latter as if the tube-gripping portion were in fact a screw being turned on the tubing but held against travelling along it. Since similarly the belt, being positioned in the axial direction by its supporting head 26, cannot progress along the tubing, the latter itself is forced to progress at a rate determined by the speed of revolution of the belt and head 25. This rate of feeding or progressing movement thus supplied to the tubing may be accurately controlled and regulated through the medium of the speed control 29. In this connect'ion the function of the paper or other flexible carrier web 6 will be appreciated. Since this tubular or partly tubular carrier layer is subject to the gripping action of the progressing means a major portion of the advancing force is received by it rather than by are being dried and the veneer layers while they set. The carrier web, being stage or structurally continuous throughout the entire length of the tubing, serves in effect as a continuous longitudinal tie or bridging connection between the various spiral turns of the tubing, relieving them of any tendency to be separated. Since in actual practice the required feeding effort axially is relatively slight, a carrier web of ordinary fairly heavy waxed paper generally is found adequate for the purpose.

Beyond the progressing or feeding station D any desired number of additional spiral applications of veneer stripping are made. We, have herein represented by way of example a further series of three stations E, F and G, each of which may be substantially similar as already described in connection with stations B and C, including heat and pressure means as exemplified at the latter station. The direction of wind is alterhated, the several wrapping heads and their drive connections, the latter again including speed control devices I6, being such as to aiford the desired reversal of lay and overlapping of edge juncture in successive layers. In the illustrated example a right lay 30 is indicated at station E, over the preceding left lay 20 at by left and right wraps 40 and 50 respectively at stations F and G. Heat and pressure treatment adequate for at least partial polymerizing of the bonding agent desirably is applied at each of these stations, similarly for example as explained in connection with station C. Thus it is evident that the operation at or in association'with each the strip there served and applied to the work substantially self-sustaining or' form retaining,

that is, each veneer wrap or layer is subject to a heat and pressure setting or polymerizing treatment prior to the serving and laying of the superposed layer next succeeding. In this manner a tubing product of maximum strength and rigidity, particularly in the radial direction as desired for the inner or core element of the tubing, is produced.

At station H we have indicated another progressing or advancing means 25 to 29. This may be-such as previously described in connection with station D. Depending on the particular characteristics, as to weight, wall thickness, and strength desired for the given tubing product, any plurality of the alternately opposite spiral veneer windings may be employed. The apparatus as here shown byway of illustration of the process makes provision for five inner or core spiral-formed layers, which plurality is upon the average found to be sufiicient in the greater number of instances, for tubing up to diameters of 3 to 5 inches or more. If additional inner wraps are desired other wrapping stations may be inserted. Conversely, if a less number of core veneer layers are required, any one or more of the stations C, E, F or G may be rendered inoperative, the corresponding wrapping head l5 being temporarily disconnected as by a zero setting of the speed control or through suitable clutch mechanism.

The forming mandrel 5 is extended through the successive wrapping stations from station A to a stage of the process as a whole such as to insure adequate support for the forming core. In the diagrammatic showing of Figs. 1, 1a, this mandrel 5 is continued through and terminates shortly beyond station H, as indicated by the dotted line and the numeral 5 on Fig. la. As previously noted, the mandrel in this instance is stationary and non-rotating, while the developing tubing product is progressed along the mandrel station C, and followed station is suflicient complete to renden or longitudinal direction.

by means such as described, the tube not being rotated on its own axis but merely advanced lineally. Beyond the forward end of the mandrel 5, as succeeding stages or'stations of the process, the resin-bonded cylindrical core or tube element itself is utilized as a mandrel for the application of the intermediate and final layers of veneer. In the illustrated example this bonded core or inner element of the tubing product comprises some five veneer layers laid spirally and alternately of the opposite hand, the particular plurality of such layers being selected as appropriate for the given tubing product.

The progressing tubular core element on continuing its advance beyond station H comes next to a station I. Here a veneer strip 50 desirably having the grain disposed lengthwise the strip is superposed on the core by laying it in the axial Such veneer strip 89 is drawn from a prepared roll supply rotatably supported as upon a cross shaft 65. The strip from such supply is led lengthwise beneath the tubing core and into and through a former or folding die 62. The latter serves to fold the lengthwise-grained strip circumferentially of the tubing core now serving as a mandrel, the strip being of the appropriate width such that its longitudinal side edges are brought into close abutting but preferably non-overlapping relation, substantially as illustrated. The described laying and lateral wrapping of this longitudinal strip is accomplished by and in the course of the continuing forward progress of the tubing as a whole.

The veneer strip 60 carries or is supplied with a bonding agent similarly as described in connection with the preceding stations and in the course of the progress of the tube at station I it is subjected to heat and pressure desirably through the medium of pressure rolls 22, 22, as at the preceding stations. In this instance, and the same applies as to all following stations, diametrically opposed pairs of the rolls 22 are disposed in circuit to receive the heating current, as indicated by the plus and minus symbols upon the drawing; that is, a pair of the rolls are utilized as the two electrodes of opposite polarity in lieu of employment of the interior mandrel as one electrode.

In some instances, but a single longitudinally applied strip such as 60 may be employed, but generally a plurality of two or more are desirable, to provide a calculated axial strength and rigidity for the tubing product in combination with the underlying spirally laid and predeterminedly radially rigid core layers. In the example of the accompanying diagrammatic illustration, two such further applications of lengthwise stripping l0 and 80 are provided for, at the station J and K respectively. In all major respects the procedure at these stations may be similar as at station I, the roll supplies of prepared lengthwise-grained veneer stripping being rotatably supported on shafts H, BI, and the succeeding strips and 80 being conducted through folding 0r forming dies 12 and 82 respectively. ,The progressing tube again is subjected to a heat and pressure treatment at each station, as by means of the indicated electrode rolls 22, whereby each individual longitudinal layer of the veneer is individually as well as progressively polymerized, set and dried.

At any convenient points with respect to the several veneer laying stations, additional progressing station are provided, one of which is indicated at station L. Th progressing or adva ing means here may be similar to that as described in connection with preceding stations D and H, including the progresser belt mechanism 25 and a speed control 29.

Following application and setting of selected 6 one or more lengthwise laid veneer strips as at stations I, J and K, one or more outer or cover veneer layers are applied, these being laid spirally similarly as at the core layer stations B, C, E, F and G. In the example a illustrated, two such final spiral layers 90 and MG are applied at station M and N respectively, these being laid of the opposite hand, indicated as right and left respectively at said stations M and N. At each of these latter stations or stages the tubing is subthe polymerizing of the bonding agent as previously described, pressure electrode roller 22, 22 being indicated for the purpose on the drawing.

A final progressing station is represented at O. This may be understood as similar to that as explained in connection with preceding stations D, Hand L.

' The continuous forward progress of the tubing product beyond station 0 brings it to the severing and delivery station such as diagrammatically represented at P. Automatic or other means is here provided for cutting off the con,- tinuous tubing product of indeterminate length into sections of any length, as may be desired for the given product and its use. At the station P a selected length of the finished tubing product is indicated a a whole by the numeral '1. It is adapted to be severed as by a swinging rotary cutter llll operated from the common drive shaft l through drive connections indicated as a whole at I02. For controlling the cutting time and point an automatic and adjustable length gauge )3 may be provided at the leading end of the tubing T, the same being movably supported and adapted to serve as a trip or stop, through connection as indicated generally at EM. Advancing engagement of the leading end of the tubing T against the trip or gauge I03 thus automatically brings the cutter lfll into operation, causirig it to swing across the path of the tubing to sever the selected length thereof, the cutter mechanism being of the timed progress type and synchronized with the progress of the tubing product so as to travel in synchronism with the latter during a cutting operation without interruptlng 0r disturbing the continued forward .progress of the following length of the tubing.

From the foregoing it will be apparent that our novel process or method provides for the production of thermo-setting or other plastic bonded plural layer veneer or plywood tubing in uninterrupted indeterminate lengths in the course of a single or unified continuous process. The process as a whole comprises a continuous series of steps or stages at a corresponding number of coordinated stations, the procedure throughout being synchronized and timed to permit the steady and uninterrupted forward progress of th rod- 5 not as a whole subject to individual manipulative control at the several stations as may be required to take care of possible'variations in the veneer strip material and the setting of the bonding agent. The method is applicable equally v to a two-directional application of the resinbonded veneer strips or layers, a for example alternated spirals or to a three-directional structure such as herein illustrated, including the one or more and herein three lengthwis; laid ye intermediate veneer layers. The described plural J'ected to a heating and pressure treatment forphase process, once instituted, is such that all phases and operation are carried out simultaneously, automatically and continuously without interruption. Proper formation of the spiral core is facilitated by utilizing a structurally continuousinterior base or carrier comprising a flexible tough web such as the waxed or other paper referred to. While such carrier, of whatever flexible sheet material, may be left in the tubing, it generally is preferred to remove it. The initial core element being spirally laid upon a non-turning mandrel while at further stages or stations the resin-bonded veneer tubing itself is utilized a a mandrel. If preferred to rotate the mandrel and the tubing formed upon it, this may be accomplished within the scope of the invention by revolving the alternately oppositely laid veneer roll supplies about the tube and mandrel at twice the speed of. rotation of the latter. The continuous process described is in large part made possible by the timing of the progress of the tubing and of the laying of the variou veneer layers to conform them to the required time interval for the polymerization of the bonding agent at each station, this in turn being made possible by polymerizing the tube during its processing at each station under a heat and pressure treatment such as described. The invention includes the novel adaptation to this end of penetrative heating by electric energy whether of the high-frequency or radio frequency character or of the transformer or resistance type and wherein at times a mandrel serve as an electrode in cooperation with outside pressure rollers or other members, or such members in opposed pairs presenting both electrodes. Through the progressive edge-turning or lateral wrapping, inturning or folding through folding dies as utilized for the length-grain veneer layers or plies or for the paper or other carrier strip 6 the rate of application thereof may be coordinated with the other phases of the process as a whole including both the inner or core stages and the exterior or cover stages, all in the synchronized, automatic and continuous procedure such as herein illustrated and described by way of example.

The continuous progression, inndeterminate length and other features of the invention as herein, disclosed and claimed are useful both in conjunction with the processes covered by the herein previously mentioned copendent Goldman Patent 2,352,533 and also otherwise. Claims for apparatus suitable for practicing the processes hereof, including apparatus as herein disclosed are contained in our divisional application Ser. No. 666,206. Claims for tubing products including among others those obtainable by the processes hereof and of said Goldman Patent No. 2,352,533 are contained in the copending Goldman applications Ser. No. 476,690, filed February 22, 1943, and Ser. No. 526,462, filed March 14, 1944.

Our invention is not limited to the particular steps or order thereof as shown or described, nor

to the particular means illustrated for the practice thereof, its scope being pointed out in the following claims.

We claim:

1'. In a continuous process for the manufacture of wood-veneer tubing, the steps which comprise spirally wrapping an initial continuous wood veneer strip into elongated closed straight tubular form and constantly advancing it along a work path defined thereby, oppositely spirally wrapping a second continuous wood-veneer strip in similar form about the first, furnishing a polylated and synchronized relation,

spirally wrapping about and merlzable bonding agent as a layer between said wraps, continuously advancing said wraps in unison along said path, longitudinally presenting and laterally wrapping a wood-veneer strip about the preceding wraps and furnishing a polymerizable bonding agent between the spiral and the lateral wraps, while continuing to advance all wrapsin unison along said path, and during continuing advance progressively applying heat and pressure to the work at each individual wrap following the second thereof prior to applying the next succeeding wrap as to polymerize the bonding agent between each two wraps so as to progressively bond together all wraps for continuous delivery of the resultant integrated tubing product.

2. In the manufacture of plural-directional multi-ply wood veneer tubing, a continuous process for progressively fabricating and uninterruptedly delivering such tubing in integral indeterminate length, which comprises, in correthe following successively-initiated and simultaneously continued steps: forming a tubular carrier of flexible sheet material on and continuously advancing it lengthwise of an elongated mandrel fining a rectilinear work path; continuously serving wood-veneer strip material and progressively wrapping it spirally into closed tubular form onto and coaxially of said carrier and advancing it with the carrier, furnishing a polymerizable bonding agent between the opposed surfaces of successive veneer wraps; applying heat and pressure to the veneer wraps thereby to bond them together during uninterruptedly continuing advance thereof; uninterruptedly supplying longitudinally at least one further woodveneer layer and laterally wrapping the same concentrically about the previous wraps; adhesively bonding such longitudinal wrap to the spiral wraps under heat and pressure applied during continued synchronous advance of all the wraps; continuously furnishing and progressively heat-and-pressure bonding to the preceding advancing wraps at least one further veneer layer; and severing the resultant continuously delivered multi-ply woodveneer tubing into lengths as required.

3. In the manufacture of wood-veneer tubin a continuous process for fabricating such tubing having a plurality of different-directional veneer plies and of indeterminate length which comprises the following simultaneous steps in correlated progressive series: individually continuously serving veneer strips from continuous supplies thereof simultaneously at a plurality of stations along a straightline work path affording intermediate treatment of the work between such stations; continuously laying such strips into closed tubular form and mutually concentric superposed relation; relatively varying the striplaying direction at different stations to afford difinitially deiii a tional plural-ply resin-bonded wood-veneer tubing of indeterminate length in a single co-= ordinate and continuous manufacturing operation.

4. A continuous process for the manufacture of muiti-directional multi-ply resin-bonded woodveneer tubing of indeterminate length, compris- -.ing, in combination: operatively presenting an elongated mandrel to initiate a straight work,

supporting another veneer strip roll supply at a 15 station in said path intermediate the helical winding stations and there longitudinally pre E2 senting and laterally wrapping said veneer strip between helical windings; etxernally engaging the work between stations and tractively advancing it continuously through all of them; supplying a synthetic resinous bonding agent at 01)- posed veneer surfaces of the Work; and continuously applying heat and pressure to the work immediately following some of the stations and in correlated time and space relation thereto and during the uninterrupted advance of the work, thereby to bond together all the veneer strips and to deliver continuously beyond the final stripapplying station a complete continuous tubing product.

PAUL R. GOLDIKQAN. RUDULPH ALT. 

